:root{
    --bgwrap:linear-gradient(to top,aliceblue,skyblue 60%,aliceblue );
    --bgflex:skyblue;
    --bgstudy:skyblue;
}
.wrap{
    background-image: var(--bgwrap);
    width: 90%;
    height: auto;
    position: absolute;
    left:0;
    right:0;
    margin-left:auto;
    margin-right: auto;
    font-size: 15px;
    display: flex;
    flex-direction: column;
}
#mycolor{
    width:auto;
    position: absolute;
    top: -5px;
    left: 10px;
}
#mycolor ul{
    display: flex;
    padding: 0;
    justify-content: space-between;
}
#mycolor ul>li{
    margin: 5px;
    border-radius: 50%;
    list-style: none;
    width: 20px;
    height: 20px;
}
#mycolor ul>li:nth-child(1){
    background-color: violet;
}
#mycolor ul>li:nth-child(2){
    background-color: skyblue;
}
#mycolor ul>li:nth-child(3){
    background-color: silver;
}
/*页脚*/
footer{
    clear: both;
    background: #999999;
    color: black;
    text-align: center;
    width: 100%;
    height: 20px;
    margin-top: 30px;
}